BEIJING — China's premier didn't say it in so many words, but the implied warning to Washington was blunt: Don't devalue the dollar through reckless spending.

Premier Wen Jiabao's message is unlikely to be misunderstood at the White House, which responded by asserting there is no safer investment in the world than the United States. It is counting on Beijing to help pay for its stimulus package by buying U.S. bonds. China already is Washington's biggest foreign creditor, with an estimated $1 trillion in U.S. government debt. A weaker dollar would erode the value of those assets.

"Of course we are concerned about the safety of our assets. To be honest, I'm a little bit worried," Wen said at a news conference Friday after the closing of China's annual legislative session. "I would like to call on the United States to honor its words, stay a credible nation and ensure the safety of Chinese assets."

The appeal suggested the outlines of Chinese President Hu Jintao's stance when he meets with President Barack Obama at an April 2 summit in London of the Group of 20 major economies on possible remedies for the global crisis.

Wen gave no indication whether Beijing wants changes in U.S. policy. But economists said his comments reflect fears that higher U.S. budget deficits from Washington's $787 billion stimulus package could drive down the dollar and the value of China's Treasury notes.

"China is telling the U.S. to be careful, not to overspend and keep an eye on the dollar," said Kelvin Lau, regional economist at Standard Chartered in Hong Kong. "There are risks that China cannot control, so they're depending on the U.S. to maintain fiscal prudence and keep the dollar reasonably stable."

Analysts estimate China keeps nearly half of its $2 trillion in foreign currency reserves in U.S. Treasuries and notes issued by other government-affiliated agencies.

"Inside China there has been a lot of debate about whether they should continue to buy Treasuries," said Frank Gong, chief China economist for JP Morgan.

Beijing is trying to increase its leverage at the London G-20 meeting by reminding its partners of its role in financing U.S. spending, Gong said.

"Without China's buying (Treasuries) and continuing to fund U.S. deficit spending, interest rates could have been much higher. That could be very destabilizing in this very recessionary environment," he said. "By attracting a lot of attention to this issue, China is already increasing its influence ahead of the G-20 meeting."

Finance officials from the G-20 meet this weekend. U.S. Treasury Secretary Timothy Geithner is pressing for a new coordinated global stimulus. Japan is supportive but European governments are reluctant to make expensive commitments before they see how current plans are working.

Wen also offered an unqualified defense Friday of his government's policies in Tibet, ignoring questions about a massive security buildup in the Himalayan region.

Tensions have spiked ahead of two key anniversaries this week — the 50th anniversary of a failed Tibetan uprising that sent the Dalai Lama into exile and Saturday's one-year anniversary of violent anti-Chinese riots in Lhasa that sparked the largest protests in decades.

Asked whether the massive security presence pointed to failings in Beijing's policies, Wen said: "The situation in Tibet is on the whole peaceful and stable. The Tibetan people hope to work in peace and stability.

"Tibet's continuous progress (has) proven the policies we have adopted are right," he said.

Wen expressed confidence the world's third-largest economy can meet its official growth target of 8 percent this year and emerge from the crisis "at an early date." But he said Beijing is ready to expand its 4 trillion yuan ($586 billion) stimulus if needed.

"We already have our plans ready to tackle even more difficult times, and to do that we have reserved adequate ammunition," he said. "That means that at any time we can introduce new stimulus policies."

Communist leaders worry about rising job losses and possible unrest amid a trade slump that saw Chinese exports fall 25.7 percent in February from a year earlier. They have promised to spend heavily to create jobs and boost exports.

Chinese bank lending and power demand have risen, suggesting the stimulus is taking effect. But growth in retail sales is weakening, indicating it has yet to spur private sector spending and investment, which analysts say will be key to its success.

Private sector economists expect growth as low as 5 percent this year. That would be the strongest of any major country but could lead to more waves of job cuts.

"I really believe we will be able to walk out of the shadow of the financial crisis at an early date," Wen said. "After this trial, I believe the Chinese economy will show greater vitality."

Wen also said Beijing wants the G-20 summit in April focus on helping the poorest countries.

The premier said Beijing has met its own commitments to help developing countries by erasing a total of $40 billion in debt owed by 46 countries and giving out 200 billion yuan ($29 billion) of aid to developing countries."

"We must see to it that we show concern for developing countries," he said.